Clear Lake
Clear Lake in Martin County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1 ft visibility. Phosphorus: 74.5 µg/L. Chlorophyll-a (algae): 52.1 µg/L. Maximum depth: 7 ft. Surface area: 267.34 acres.
- Clarity
- 1 ft
- Typical in August
- 80°F
- Max depth
- 7 ft
- Area
- 267 acres
- Type
- Hypereutrophic
- Public access
- Yes
- Ice-out
- Mar 21
- Open water
- 256 days
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Clear Lake →
Next lake in Martin County
Clear Lake is a 267-acre highly nutrient-loaded hypereutrophic lake in Martin County, Minnesota with a maximum depth of 7 feet. Water quality is graded F based on 2 sampling years through 2025. The lake supports 12 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 1 public boat landing. Compared to the 11 other monitored lakes in Martin County, Clear Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-16. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
Very murky, less than 1 ft of visibility. Phosphorus level: 74.5 µg/L. Chlorophyll-a: 52.1 µg/L. Trophic State Index: 71.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1 ft | Not graded |
| Phosphorus | 74.5 µg/L | Poor |
| Chlorophyll-a (Algae) | 52.1 µg/L | Poor |
| Trophic State Index (TSI) | 71 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Clear Lake
Compare lakeside cabins, hotels, and vacation rentals near Clear Lake in Martin County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Clear Lake are listed below.
Top-rated places to stay near Clear Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Clear Lake typically sits around 80°F at the surface in August. Summer average is about 78°F. Usually warmest in Jul (about 80°F) and coldest in May (about 55°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 15 field readings (2025–2025) via the EPA Water Quality Portal. See the full Clear Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Clear Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was very high (1,419,058 cells/mL) on July 18, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 7 ft |
| Surface Area | 267 acres |
| Shoreline Length | 2.7 mi |
| Littoral Zone | 100% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Clear LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Clear Lake
Ice Season
Historical ice data from Minnesota DNR (9 observations).
Estimated open water season: 256 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2026-03-09 (2026) | 2023-04-11 (2023) |
| Ice-In | 2025-11-28 (2025) | 2017-12-07 (2017) |
Most recent ice-out: 2026-03-09
County Ranking
Ranked #2 of 12 lakes in Martin County
Nearby Lakes in Martin County
Frequently asked questions about Clear Lake
What is the water quality grade for Clear Lake?
- Clear Lake in Martin County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1 ft visibility. Phosphorus: 74.5 µg/L. Chlorophyll-a (algae): 52.1 µg/L. Maximum depth: 7 ft. Surface area: 267.34 acres.
Is Clear Lake safe to swim in?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Clear Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 52.1 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Clear Lake?
- Clear Lake typically sits around 80°F at the surface in August, from 15 EPA Water Quality Portal field readings (2025–2025). That is a typical value for the month, not a live reading.
How deep is Clear Lake?
- Clear Lake has a maximum depth of 7 feet. The lake covers 267.34 acres.
What fish are in Clear Lake?
- Fish species found in Clear Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, channel catfish, common carp, orangespotted sunfish, walleye, white crappie, white sucker, yellow bullhead, yellow perch. Clear Lake is located in Martin County, Minnesota.
When does Clear Lake thaw?
- Clear Lake typically has ice-out around Mar 21. Ice typically forms around Dec 2. The open water season is approximately 256 days.
Does Clear Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Clear Lake (clouds, ice, or an off-season gap). The most recent reading was very high (1,419,058 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Clear Lake?
- Clear Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Clear Lake. Public access is listed as yes.
Explore Clear Lake across LakeGrade
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Species activity outlook by water temperature and season
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Where this data comes from
15 measurements from 1 monitoring station, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA15 samples · 2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate